1. Field of the Invention
This invention relates to an area specifying signal generation device using an output signal from a video camera.
2. Description of the Related Art
A camera-integrated type VTR which has a video camera and a video tape recorder formed integrally with each other is known in the art. The camera-integrated type VTR has a function called a title insert.
When the title insert function is effected, the camera-integrated type VTR is set into the title photographing mode at the first stage. In this state, if a subject (white rectangular paper) on which the title is previously drawn is set in the visual field of the camera and photographed, an image signal thus obtained is converted in a digital signal and stored in a memory. When the camera-integrated type VTR is changed from the ordinary photographing mode to the title insertion mode at the second stage, an area specifying signal which specifies an area corresponding to the title portion is read out from the memory. The area specifying signal controls a switch provided in the signal path for a video signal derived by the current photographing operation so as to convert portions of the video signal corresponding to the title into a black or white level. As a result portions of the video signal derived by the current photographing operation are replaced by the title letters at the black level, thus permitting the title to be inserted into the video signal.
The title insert function permits a picture elimination process to be effected. The picture elimination process is to replace portions of the video signal currently produced by a black level signal, for example. In order to effect the process, the camera-integrated type VTR is first set into the title photographing mode. Then, a subject having a portion previously painted black is photographed and then an area specifying signal specifying the black level area is stored in the memory. After this, when the camera-integrated type VTR is changed from the ordinary photographing mode to the title insertion mode, the area specifying signal specifying the black level area is read out from the memory. The area specifying signal controls a switch provided in the signal path for a video signal derived by the current photographing operation so as to convert portions of the video signal into a black or white level signal. As a result, portions of the image signal are fully replaced by the black or white level signal, thus causing the picture to be selectively removed.
With the conventional camera-integrated type VTR described above, for example, a sheet of white rectangular paper is prepared in order to store elimination data into the memory. The white paper is set in the visual field of the camera and a partial area of the paper to be subjected to the picture elimination process is painted black. The paper thus painted is photographed by the camera-integrated type VTR set in the title photographing mode. Then, the black-painted portion is photographed so as to produce black level data which is in turn stored into the memory.
As described above, in the conventional system, it is necessary to paint a partial area of the white paper corresponding to the picture elimination area black in order to store black level data for picture elimination into the memory. For this reason, the user must paint a larger area black as the picture elimination area becomes larger. Such an operation is extremely troublesome for the user.